An explosion rocked the western Iranian city of Isfahan on Monday, the semi-official Fars news agency reported, adding that the blast was heard in several parts of the city.

According to reports, frightened residents called the fire department after the blast, forcing the city authorities to admit there had been an explosion.Residents reported that their windows shook from the explosion’s force.

Speaking to an Iranian news website, the government of Isfahan said that the explosion occurred as a result of a military drill, denying reports that the blast was somehow related to the nearby nuclear facility.

. . . the destruction of the Iranian nuclear program is the subject of my latest Devlin thriller, Shock Warning. Each of the three installments in the series so far has dealt with one or more national-security nightmare scenarios, including a school-hostage situation and an EMP attack (Hostile Intent) and a Bombay-style assault on Times Square (Early Warning).

To paraphrase Oscar Wilde, the good end mostly happily and the bad unhappily; that is what fiction means. But in its combination of psywar, the Stuxnet virus, and direct action, Shock Warning comes pretty close to various special-ops maneuvers either bruited or already under way.